Five abstracts selected for poster presentation at the American Association for Cancer Research (AACR) Annual Meeting 2022 Data highlight progress on Cullinan Oncology’s pipeline of therapeutic candidates CLN-049 (Florentine), CLN-619 (MICA), CLN-617 (Amber), CLN-978 (NexGem), and a novel PD-1 x CD137L fusion protein (Opal) CAMBRIDGE, Mass., March 08, 2022 (GLOBE NEWSWIRE) — Cullinan Oncology, Inc. (NASDAQ: CGEM) (“Cullinan”), a biopharmaceutical company focused on developing a diversified pipeline of targeted therapies for cancer patients, today announced that it will present data across five distinct immuno-oncology programs at the American Association for Cancer Research (AACR) Annual Meeting taking place April 8-13, 2022 in New Orleans. “We are proud to present data across our deep pipeline at AACR 2022 and look forward to sharing our latest research on five immuno-oncology therapies with best- and/or first-in-class potential for patients with cancer,” said Patrick Baeuerle, Ph.D., Chief Scientific Officer, Biologics, of Cullinan Oncology. “The programs that we are presenting at AACR are immune-activating biologics that may alter the tumor microenvironment, co-activate innate and adaptive immunity, or engage T cells for cancer therapy. Our mission is to develop molecules that set a new standard of care in the treatment of cancer and to find solutions for patients in critical need of more effective therapeutic options.” Overall, five abstracts were selected for poster presentations. Data for the following programs will be presented: Preclinical characterization of CLN-049 and demonstration of its antitumor activity in AML models. CLN-049 demonstrated potent FLT3 target-dependent leukemic cell killing and T cell activation in vitro against cells regardless of FLT3 mutational status, while sparing key normal hematopoietic cell populations. CLN-049 also demonstrated dose dependent anti-tumor efficacy and improved survival in mouse leukemic models. CLN-049 is a FLT3/CD3-bispecific T cell-engaging antibody in an IgG format for the treatment of acute myeloid leukemia (AML), the most common form of acute leukemia in adults with few options for curative treatment. A more extensive preclinical characterization of CLN-049 has been accepted for publication in the Journal for Immunotherapy of Cancer (JITC), titled, “A Novel IgG-based FLT3xCD3 Bispecific Antibody for the Treatment of AML and B-ALL.” CLN-049 is currently in a phase 1 clinical trial for the treatment of patients with relapsed/refractory AML.Preclinical data evaluating the ability of CLN-619 to functionally restore the MICA/MICB-NKG2D axis and enhance the binding of MICA to NKG2D on NK cells. CLN-619 is a first-in-class monoclonal antibody that stabilizes MICA/MICB on the tumor cell surface to promote an antitumor response via activation of both natural killer (NK) cells and certain T cells. CLN-619 is being developed for the treatment of multiple cancer indications and is currently being investigated in a phase 1 clinical trial for the treatment of patients with advanced tumors as a monotherapy and in combination with checkpoint inhibitor therapy. Preclinical data demonstrating robust anti-tumor activity of CLN-617, locally in injected tumors and systemically in uninjected tumors. CLN-617 is a first-in-class cytokine fusion protein uniquely combining IL-2 and IL-12 with a collagen binding domain for retention in the tumor microenvironment (TME). Intratumoral retention significantly improves the overall tolerability and efficacy of the cytokine combination. The program is in IND-enabling studies.Preclinical characterization of CLN-978, a novel CD19/CD3-bispecific construct with extended serum half-life and high potency against target cells expressing very low levels of CD19. The program is in IND-enabling studies.Preclinical data assessing Opal, an earlier stage immuno-oncology program designed to simultaneously block the PD-1/PD-L1/2 axis and conditionally activate the 4-1BB/CD137 pathway on T cells. The selected abstracts are now available on the AACR conference website here. Poster presentation details are listed below: Presentation Details:Program: CLN-049 (Florentine)Title: CLN-049 is a bispecific T cell engaging IgG-like antibody targeting FLT3 on AML cellsAbstract Number: 2078Poster Number: 15Session Date & Time: Monday, April 11, 2022 at 1:30-5:00 p.m. CDT/2:30-6:00 p.m. EDT Location: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 38 Program: CLN-619 (MICA)Title: CLN-619, a clinical-stage MICA/MICB-specific IgG1 antibody, restores the MICA/MICB-NKG2D axis to promote NK-mediated tumor cell lysisAbstract Number: 3506Poster Number: 8Session Date & Time: Tuesday, April 12, 2022, at 1:30-5:00 p.m. CDT/2:30-6:00 p.m. EDTLocation: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 37 Program: CLN-617 (Amber)Title: CLN-617 is an IL-2/IL-12 fusion protein with a collagen-anchoring domain that induces potent systemic anti-tumor immunity upon intra-tumoral administrationAbstract Number: 3505Poster Number: 7Session Date & Time: Tuesday, April 12, 2022, at 1:30-5:00 p.m. CDT/2:30-6:00 p.m. EDTLocation: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 37 Program: CLN-978 (NexGem)Title: Preclinical characterization of a next-generation CD19/CD3-bispecific T cell engager with extended serum half-life and superior potency against CD19-low target cellsAbstract Number: 2077 Poster Number: 15Session Date & Time: Monday, April 11, 2022, at 1:30-5:00 p.m. CDT/2:30-6:00 p.m. EDTLocation: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 38 Program: PD-1 x CD137L fusion protein (Opal)Title: Opal is a conditional 4-1BB agonistic fusion protein comprising trimerized 4-1BB ligand and a high affinity variant of the extracellular domain of PD-1Abstract Number: 2076Poster Number: 14Session Date & Time: Monday, April 11, 2022, at 1:30-5:00 p.m. CDT/2:30-6:00 p.m. EDT Location: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 38 About Cullinan Oncology Cullinan Oncology is a biopharmaceutical company that is developing a diversified pipeline of targeted therapeutic candidates across multiple modalities in order to bring important medicines to patients with cancer. The Company’s strategy is to source innovation through both internal discovery efforts and external collaborations, focusing on advanced stage assets with novel technology platforms and differentiated mechanisms. Learn more about Cullinan Oncology at www.cullinanoncology.com. Forward-Looking Statements This press release contains forward-looking statements of Cullinan Oncology, Inc. (“Cullinan,” “we” or “our”) within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, express or implied statements regarding Cullinan’s beliefs and expectations regarding our preclinical and clinical development plans, clinical trial designs, clinical and therapeutic potential, and strategy of our product candidates, including but not limited to our expectations and beliefs around the safety and activity of its CLN-049, CLN-619, CLN-617, CLN-978 and PD-1 x CD137L fusion protein programs. Any forward-looking statements in this press release are based on management’s current expectations and beliefs of future events, and are subject to known and unknown risks and uncertainties that may cause our actual results, performance or achievements to be materially different from any expressed or implied by the forward-looking statements. These risks include, but are not limited to, the following: uncertainty regarding the timing and results of regulatory submissions; success of our clinical trials and preclinical studies; risks related to our ability to protect and maintain our intellectual property position; risks related to manufacturing, supply, and distribution of our product candidates; risks related to the impact of COVID-19 affecting countries or regions in which we have operations or do business, including potential negative impacts on our employees, customers, supply chain and production as well as global economies and financial markets; the risk that any one or more of our product candidates, including those that are co-developed, will not be successfully developed and commercialized; the risk that the results of preclinical studies or clinical studies will not be predictive of future results in connection with future studies; and success of any collaboration, partnership, license or similar agreements. These and other important risks and uncertainties discussed in our filings with the Securities and Exchange Commission, or SEC, including under the caption “Risk Factors” in our most recent Annual Report on Form 10-K and subsequent filings with the SEC, could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release. Moreover, except as required by law, neither Cullinan nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements included in this press release. Any forward-looking statement included in this press release speaks only as of the date on which it was made. We undertake no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law. Contacts: Investor Relations Lee Roth / Dr. Grace Kim +1 212.213.0006 Lroth@burnsmc.com / gkim@burnsmc.com Jeffrey Trigilio +1 617.410.4650 jtrigilio@cullinanoncology.com Media Rose Weldon +1 215.801.7644 rweldon@cullinanoncology.com